#include<iostream>
#include<unordered_map>
using namespace std;
int main(){
    int n;
	cin>>n;
	unordered_map<int,int> m;
    for(int i=0;i<n;i++){
    	int num;
    	scanf("%d",&num);
    	m[num]++;
	}
	for(auto it:m)
		if(it.first%2==1&&it.second%2==1){
			cout<<it.first;
			break;
		}		
	return 0;
}
